CCI-779 is an ester analog of the immunosuppressive agent sirolimus and it has demonstrated significant inhibitory effects on tumor growth in both in vitro and in vivo models. It has a novel anti-tumor mechanism of action that results in the inhibition of translation of several key proteins that ultimately results in a block in the G1 phase of the cell cycle. This study will demonstrate the safety, tolerability, and pharmacokinetics of CCI-779 given intravenously once daily for five days, every two weeks in patients with advanced solid tumors. It will also determine the safety and tolerability and identify the maximum tolerated dose in patients with recurrent gliomas or brain metastases from other tumors who are receiving anticonvulsants.